It’s an example of 8051 Calculator with 16×2 LCD and Telephone Keypad.
This example project describes how can we interface 16×2 LCD and keypad. Simple Telephone keypad is used for this project. Initially when system is started 0 is displayed on 2nd row and right most column. First user enters first operand then select an operation by pressing ‘*’ key once or again and again. When user presses ‘*’ key first multiply operation is displayed on left most upper corner. By pressing ‘*’ key again and again changes operation to be performed and this operation is displayed on upper left corner of the 16×2 LCD. Operation in this version are simply 4 arithmetic operations *,+,- and /. Maximum of 4 digit operand can be entered in this version. After selecting operation user will enter 2nd operand then press ‘#’ key that will perform selected operation and will show result on lower right corner of 16×2 LCD.
For detail of LCD interfacing please see 8051 To 16×2 LCD Interfaing.
For basic operation & components used in an 8051 based microcontroller based systems see
8051 Basic LED Flasher.